2022 Yes https://www.mdpi.com/2305-6304/10/9/545 Park, Su-Hoon Asia Observational Ventilation rates Classrooms Ventilation Indoor air quality Age of air Computational fluid dynamics In the classroom with the existing ventilation system, the age of air was low in the area near the ventilation inlets, while air congestion areas were widely distributed and air age was high near the outlets. Conversely, in the vertical airflow classroom, the average age of air was approximately 15% lower than that with the existing ventilation system, and the deviation of air age for each position in the classroom space was also reduced, showing a uniform air age distribution. Therefore, the vertical airflow ventilation system proposed in this study can be an effective ventilation scheme for enhancing and homogenizing indoor air quality.